Extra Spell Chameleon
The Chameleon prestige class has the only available floating feat (that I know of) in D&D 3.5
One well known trick is to use the floating feat to take Extra Spell over and over again, allowing the Chameleon to make a spell book with any spell they like (and craft utility scrolls of up to 5th spell level).
Extra Spell is limited by only allowing you to learn a spell of 1 level lower than your highest you can currently cast. Is there a way to boost the Chameleon's spell level up to 7 so it can access the 6th level spells on the Wizard/Sorcerer list?